Bishop Gassis was succeeded Oct. 28 by his coadjutor, Bishop Michael Didi Adgum Mangoria, 54, who has served as apostolic administrator of the diocese since August, 2010.

Bishop Gassis had been head of the diocese since May 1988. He joined the Comboni Missionaries of the Heart of Jesus in 1957, and was ordained a priest for the institute of consecrated life in 1964.

He celebrated his 75th birthday on Sept. 21.

The El Obeid diocese covers more than 340,000 square miles in western Sudan, including all of the Darfur region, as well as part of South Sudan. In 2006, 151,200 persons in the diocese were Catholic, or 1.6 percent of the population. At that time, the diocese was served by 23 diocesan priests, and 12 religious. Around 97 percent of the Sudanese population is Muslim.

Bishop Gassis helped establish what is now known as the Sudan Relief Fund, a Virginia-based non-profit that has worked to support Catholic hospitals, a Catholic radio station, schools, water projects, food provisions and refugee kits. The organization also supports Catholic evangelization.

“May God bless Bishop Gassis on his 75th birthday, and always. Please join us in prayer for this good servant and shepherd and in thanksgiving for his life and witness,” Sudan Relief Fund announced recently on its website.

The fund recently changed its name from the Bishop Gassis Sudan Relief Fund in order to express an “expanded mission” to partner with other bishops, religious orders, and Catholic organizations throughout South Sudan.

“Under our new name we will continue to help the Church carry on the critical work of easing the suffering and saving lives of the persecuted people of South Sudan.”

Sudan and South Sudan were unified until July 2011, when South Sudan became independent seven months after a referendum.

The region suffered a severe 20-year-long civil war that killed an estimated two million people. The war inflicted atrocities such as religious persecution, enslavement, torture, rape, murder, and other crimes, until the war’s end in 2005.